Allow tuning of heaptargetutilization

Remove a pair of explicit sets of this value.  This allows ART to tune
this parameter to improve GC responsiveness and memory usage.  Tuning
this parameter is a key area of work for OEM-requested high-memory
device configurations.

Bug: 145823510
Test: boot and run with various configurations of the flag.
Change-Id: I19680ff5fa1ebf9dfd4a3f71533d03510f4da414

core/java/com/android/internal/os/RuntimeInit.java

@@ -30,8 +30,10 @@ import android.os.SystemProperties;
 import android.os.Trace;
 import android.util.Log;
 import android.util.Slog;
+
 import com.android.internal.logging.AndroidConfig;
 import com.android.server.NetworkManagementSocketTagger;
+
 import dalvik.system.RuntimeHooks;
 import dalvik.system.VMRuntime;
 
@@ -374,9 +376,6 @@ public class RuntimeInit {
         // leftover running threads to crash before the process actually exits.
         nativeSetExitWithoutCleanup(true);
 
-        // We want to be fairly aggressive about heap utilization, to avoid
-        // holding on to a lot of memory that isn't needed.
-        VMRuntime.getRuntime().setTargetHeapUtilization(0.75f);
         VMRuntime.getRuntime().setTargetSdkVersion(targetSdkVersion);
 
         final Arguments args = new Arguments(argv);

services/java/com/android/server/SystemServer.java

@@ -448,10 +448,6 @@ public final class SystemServer {
             // Mmmmmm... more memory!
             VMRuntime.getRuntime().clearGrowthLimit();
 
-            // The system server has to run all of the time, so it needs to be
-            // as efficient as possible with its memory usage.
-            VMRuntime.getRuntime().setTargetHeapUtilization(0.8f);
-
             // Some devices rely on runtime fingerprint generation, so make sure
             // we've defined it before booting further.
             Build.ensureFingerprintProperty();